I've now had two back to back games that got stuck in the middle of a turn with a grayed out "Idle Ship" being displayed on the Turn button. I abandoned the first one thinking it was a one off fluke, but this is twice in a row. Both times were on the newest 1.12 update and I hadn't had this issue before.
Both games got stuck around turn 240-ish. Both were Insane maps on Godlike difficulty with vanilla races.
In my current game, I was able to continue by saving the game, exiting all the way out and reloading. Being able to save the game mid turn seemed odd to me and I tried to do it again on another turn, but it doesn't let you save the game if the turn is active. So if you can save in the middle of the turn when it's stuck, it seems that you can continue where you left off.
I've read about others who had to back up a couple of turns, but this way, you can save some frustration.